1. Field
This invention relates to apparatus for separating a carrier fluid from solids suspended within that fluid. More particularly, the invention is directed to clarifier apparati used for slurry processing which utilize gravity to effectuate a liquid/solids separation.
2. State of the Art
Various clarifier systems for use in separating carrier fluids from suspended solids are known in the art. Such systems typically include a vessel having an inlet and an outlet. The inlet and outlet are positioned to establish a flow path for a stream of fluid mixture introduced into the vessel. A separation unit is oriented within that flow path to intercept the stream of mixture and separate the carrier fluid from the solids suspended within the fluid. The clarified carrier fluid is thereafter channeled off into one receiving area while the solids are directed to another.
U.S. Pat. No. 3,951,818 (Bosnjak) discloses a clarifier of the gravity separation type. This clarifier includes a vertical upright channel defined by a pair of oppositely positioned separation elements. Each of the separation elements includes a vertical plate which is interseted at spaced intervals along its height by outwardly extending flow directioning plates. The directioning plates intersect the vertical plate at an acute angle; i.e., the directioning plates are arranged at an angle to the horizontal plane.
The vertical plates each define a plurality of sized orifices, positioned proximate each intersection of the vertical plate with a flow directioning plate, more specifically, proximate an apex formed by that intersection. Each of the orifices communicates with the vertical channel thereby establishing a pathway from the body of the fluid mixture to the vertical channel.
The Bosnjak separation elements are suspended within a receiving vessel by two upright supports which are spacedly positioned one from another. The supports include a plurality of outwardly extending rods. An apex of each separation element is formed by the intersection of the vertical support with a directioning plate. This apex is placed over a respective support rod and thereafter is held in position by the action of the rod against the apex.
In operation, clarifiers of the kind typified by the Bosnjak structure have experienced difficulty in operation. Due to the structures of the clarifiers, the vertical plates are not held in a sealed relationship with upright supports. These upright supports form the sides of the plurality of compartments defined by the association of the vertical plate, directioning plates and supports. As a result of the unsealed relationship, short circuiting of the separation process occurs. Specifically, unclarified mixture may bypass the gravity separation action of the compartments by flowing around the vertical plates directly into the vertical channel. This short circuiting action results in the clarified carrier fluid within the vertical channel being contaminated by an infusion of the unclarified fluid mixture. This contamination imposes a practical limitation on the separation efficiency of the clarifier apparatus and, more specifically, on the concentration of clarified carrier fluid obtainable by use of the apparatus.
The requirement of a vertical channel makes clarifiers of the Bosnjak construction relatively spatially large. Considering that clarifiers may be installed in spatially restricted environments, such as in mines, the spatial requirements of this clarifier construction may prove disadvantageous.
U.S. Pat. No. 4,544,487 (Bosnjak) discloses a clarifier system composed of back-to-back positioned separation elements. Each element includes a vertical plate intersected at spaced intervals by outwardly extending flow directioning plates similar to those disclosed in U.S. Pat. No. 3,951,818. The vertical plate and flow directioning plates form a series of apexes similar to the construction described above. The latter structure differs from the former in that the apexes include a curved wall which substantially confines the area extant between each intersection of the vertical plate and a directioning plate thereby forming an open-ended horizontally oriented pipe. This horizontal pipe together with the channel defined thereby functionally substitutes for the vertical channel of the former construction as a means of withdrawing clarified carrier fluid from the clarifier.
While clarifier configurations of the type disclosed in U.S. Pat. No. 4,544,487 remedy the short circuiting complications of clarifiers, such clarifiers engender a different problem. Specifically, clarifiers are often subjected to severe loading induced stresses during their installation and use. Oftentimes, the carrier pipes and flow directioning plates have become separated from their supports either during installation or use.
In view of the disclosed clarifiers, there exists a need for a clarifier system which circumvents the possibility of the fluid mixture short circuiting the clarifier process, while at the same exhibits a sufficiently structural integrity to withstand the stresses encountered during installation and operation.